1. Field of the Invention
This invention relates to a novel charging system for solid materials into vertical reactors such as vertical ovens, chemical reactors, cupolas, ferrous and non-ferrous blast furnaces, shaft furnaces, chemical reactors and the like without the use of locks, conventional flap valves, gates, pressure chambers, doors or bells but by means of electronic control of the exhaust gases.
2. Description of Prior Art
Previous art for charging systems for vertical metallurgical and chemical reactors and furnaces is very extensive.
In order to provide background information so that the invention may be completely understood and appreciated in its proper context, reference may be made to a number of prior patents and publications as follows:
U.S. Pat. No. 5,133,801 to Saarinen, relates to a method and apparatus for feeding solid material into a smelting furnace, particularly into the top part of the reaction space of a smelting furnace. The solid material is supplied through a feed gate to the reaction space.
U.S. Pat. No. 5,046,908 to Cimenti is directed to a deflecting plate within the hopper, said plate having a closed position for closing the bottom end of the hopper and said plate being movable vertically upwardly from the closed position to define an annular orifice at the bottom end of the hopper and means for moving the deflecting plate vertically within the hopper.
U.S. Pat. No. 4,949,940 to Webber concerns a separating wall into a lower distributor chamber and an upper lock chamber to which the charging material can be fed from above through a filling hopper. Outside its middle and distributed around its periphery, the separating wall includes at least two individually closable bottom openings through which the charging material can be passed from the lock chamber into the distributor chamber. The charging material is fed to the shaft furnace through distributor pipes which connects the distributor chamber to the shaft furnace.
U.S. Pat. No. 4,881,869 to Henneken involves a furnace wherein while a material is being charged in the upper hopper, one of the charging valves is open and the bellows is pressureless. During, or shortly after the charging, the upper hopper is rotated. For filling the lower hopper, the valves of the upper hopper are closed, bellows is inflated, and the upper sluice chamber is pressurized.
U.S. Pat. No. 4,820,105 to Legile provides two containers mounted there above provided with sealing valves and a metering member.
U.S. Pat. No. 4,728,240 to Bernard wherein above the chamber are arranged at least two locks which are each provided with upper and lower sealing flaps. Preferably, the storage hopper and the bottom of each of the locks are in the configuration of tapered funnels.
U.S. Pat. No. 4,708,643 to Fugger discloses a feed container designed to constitute a lock chamber, which is provided with a shut-off valve for controlling the inlet port of the feed container and with a plurality of shut-off valves for controlling respective outlet ports connected to the charging ducts.
U.S. Pat. No. 4,322,197 to Wurth involves a material to be deposited on the hearth of a shaft furnace serially passes through a pair of temporary storage containers positioned above the furnace. The uppermost storage container is in the form of a bin open to the ambient atmosphere while the lower storage container is provided with valves at either end whereby it may be hermetically sealed and subsequently brought to furnace pressure. The lower storage container is loaded while at ambient pressure, by releasing furnace charge material previously delivered to the upper storage container into the lower container and subsequently by delivering material directly to the lower container from a conveyor system through the lower container. The upper container is refilled with material while the lower container is at furnace pressure and is discharging its contents into the furnace.
U.S. Pat. No. 4,116,345 to Greaves is directed to an apparatus which includes a gas lock means for introducing charge material into the furnace while the furnace is under gas pressure, and a distributor means below the gas lock means that causes the charge material to be deposited and distributed in the upper portion or throat of the furnace either toward the outer periphery of the cross section in the furnace bounded by the interior surface of the furnace wall or toward the center of such cross section, or in both places, to provide an upper surface or stockline or charge material that is essentially level or of any other desired shape within substantial limits. One form of distributor means disclosed comprises a vertically movable distributor bell with an upwardly and inwardly converging top surface that is positioned with the lower edge of such surface positioned either above or below the bottom edge of an opening, larger than the bell diameter, in a distributor hopper with upwardly outwardly diverging sides, so that the material charged into the hopper through the gas lock means can by cooperation of the bell and hopper be deflected either toward the outer periphery or toward the center of the cross section within the furnace or toward any intermediate location, by disclosed positioning or movement of the bell.
U.S. Pat. No. to 4,050,592 to Greaves relates to the bottom edge of an opening, larger than the bell diameter, in a distributor hopper with upwardly outwardly diverging sides, so that the material charged into the hopper through the gas lock means can by cooperation of the bell and hopper be deflected.
U.S. Pat. No. 4,001,488 to Bruff involves a feed chute, i.e., a valve associated with each said charging chute towards the first end thereof, each said valve being operative.
U.S. Pat. No. 3,880,306 to Grewer discloses a pellet feed which is stopped and the input is blocked by a pivotal bell. The bottom of the bucket which is formed by another linearly displaceable but pivotally suspended bell, is then displaced downwardly away from the sides of the bucket and a bell temporarily blocking the outlet is also moved downwardly to allow the mass of pellets in the bucket to spill out and down into the furnace. The bells, thus form alternatively effective inlet and outlet gates sealing the head of the furnace against the escape of gas.
U.S. Pat. No. 3,796,419 to Roenick relates mounted on the upper portion of the furnace portion, above two furnace bells in superposed stationary hoppers. Each of the port means has an upwardly open mouth, and individual valve means for closing the port means gas tight and for opening the port means independently of other port means so it can provide an unimpeded flow of material into the furnace.
U.S. Pat. No. 3,788,621 to Nieboer involves a valve which includes an annular sealing lip which engages into a seat defined on the exterior of the hopper around the exterior of the bell and engages with the seat at a location above the sealing seat defined at the interior of the hopper and which is engaged by the small bell. The small bell dams the material at the outlet of the hopper and a lower larger bell provides a distribution for the material and is located within the furnace below the small bell.
U.S. Pat. No. 3,780,890 to Glover concerns several individual port means which are spaced around the axis and mounted on the upper portion of the furnace above two superposed furnace bells in superposed stationary hoppers. Each of the port means has an upwardly open mouth, and individual valve means for closing the port means gas tight and for opening it independently of other port means so it can provide a flow of material into the furnace.
U.S. Pat. No. 3,759,404 to Mahr is directed to a charging device for a shaft furnace, comprising an upper chamber, a lower chamber communicating with the upper chamber, an upper charging bell in the upper charging chamber, and a lower charging bell below the lower chamber.
U.S. Pat. No. 3,796,387 to Tokarz relates to an apparatus including a revolving multi-chamber distributor hopper with swing valves to define a gas seal below the distributor hopper and material gates to prevent discharge of material on to the swing valves.
U.S. Pat. No. 3,704,992 to Nieboer involves having a top pan with a distributor bell therein which is movable upwardly to close the top pan to permit an accumulation of charging material thereover and which may be moved downwardly to provide an annular charging opening for the material to drop off the bell into the furnace.
U.S. Pat. No. 3,695,466 to Sugawara pertains to an apparatus for charging raw materials or ore rocks into a furnace, and uses four bells namely a large bell, a middle bell, a small bell and a rotating hopper bell serving as the charging apparatus for the furnace, and these bells are formed so as to provide sealing and charging or distributing functions and each of them is suitably operated to smoothly charge raw materials.
U.S. Pat. No. 3,693,956 to Nieboer relates to a charging device for a metallurgical furnace includes a hopper and a bell assembly which are positionable in a furnace head. The hopper is pivotally mounted below a storage bin and it may be oriented by push rods to drop the charged material in any desired direction. A distributor bell is mounted within the furnace head on supporting rods in a position such that the outer periphery thereof may be engaged with a top pan portion of the furnace to provide a seal for preventing the further down flow of the charging material but not for the purpose of providing a pressure gas seal.
U.S. Pat. No. 3,679,192 to Powell is directed to an improvement in a bell and bell hopper top charging device for use with a blast furnace comprises a retaining surface that projects upwardly from a frusto-conical surface of the bell to form a pocket between the frusto-conical surface and the retaining surface. This pocket is filled with raw materials. Upon lowering the bell from the bell hopper to discharge the raw materials from the bell hopper, the raw materials flow over the retained material in the pocket and out of contact with the sealing surface of the bell. The improvement further comprises a supplemental sealing means that is mounted to the bell hopper for engagement with the sealing surface of the bell for maintaining a gastight seal between the bell and the bell hopper.
Whatever the precise merits, features and advantages of the above cited references, none of them achieves or fulfills the purposes of the process described in this invention. The previous art for charging solid materials in vertical reactors, furnaces, and at the same time to prevent the exhaust gases from escaping to the atmosphere, has traditionally used locks, conventional flap valves, gates, pressure chambers, doors or bells, as can be seen by reading the previous references. The mentioned devices, have a high initial cost and extensive maintenance due to the temperature and the corrosion that they are exposed. The invention provides a unique simple process, to eliminate the previous disadvantages, by means of a bellow-charge-gas-off-take, measuring a gas flow and by electronically controlling of the exhaust gases by a servo valve, after the gases are cooled and cleaned. With this invention, it is possible to load solid charge materials at all times, into the reactor without loss of gases to the atmosphere or the intake of air into the gases.